SEW电机抱闸调整及间隙数据

1

1.3Principles of the SEW brake 1.3.1Principles of project planning The SEW brake is a DC-operated electromagnetic disc brake with a DC coil which is opened electri-cally and braked using spring force. The system satisfies fundamental safety requirements: the brake is applied if the power fails.The principal parts of the brake system are the brake coil itself (accelerator coil + coil section =holding coil), consisting of the brake coil body (9) with an encapsulated winding and a tap (8), the moving pressure plate (6), the brake springs (7), the brake disc (1) and the brake bearing end shield (2).The significant feature of SEW brakes is their very short length: the brake bearing end shield is a part of both the motor and the brake. The integrated construction of the SEW brake motor permits particularly compact and sturdy solutions.00871AXX Fig. 1: Block diagram of the brake 1Brake disc 2Brake bearing end shield 3Carrier 4Spring force 5Working air gap 6Pressure plate 7Brake spring 8Brake coil 9 Brake coil body 10Motor shaft 11 Electromagnetic force 5111098763214

1

1.3.2Basic function

In contrast to other DC-operated disc brakes, SEW brakes operate with a two coil system. The pressure plate is forced against the brake disc by the brake springs when the electromagnet is de-energized. The motor is braked. The number and type of the brake springs determine the braking torque.

When the brake coil is connected to the appropriate DC voltage, the spring force (4) is overcome by magnetic force (11), thereby bringing the pressure plate into contact with the brake coil body.The brake disc moves clear and the rotor can turn.

Particularly short response times When switching on:

A special brake control system ensures that only the accelerator coil is switched on first followed by the holding coil (entire coil). The powerful impulse magnetization (high acceleration current) of the accelerator coil produces an especially short response time, particularly in large brakes, with-out however reaching the saturation limit (→ Fig. 2). The brake disc moves clear very swiftly and the motor starts up with hardly any braking losses.

00868AEN

Fig. 2: Functional principles of the two coil brake BS Accelerator coil 1) Brake I B

Acceleration current

TS Coil section 2) Brake control system I H Holding current BS + TS = Holding coil M 3TS

BS

1)2)

V AC

01873AEN

120ms

I B

t

I H

Acceleration Holding

1

The particularly rapid response times of SEW brakes add up to a shorter motor startup time, mini-mum startup heating and therefore less energy consumption and negligible brake wear during startup (→ Fig. 3). These factors pay dividends to the user in the form of an extremely high starting frequency and long brake service life.00869AXX Fig. 3: Shortening the motor startup time with the SEW brake system The system switches over to the holding coil electronically as soon as the SEW brake has released.The braking magnet is now only sufficiently magnetized (with a small holding current) to ensure that the pressure plate is held in the startup position with adequate security and with minimum brake heating (→ Fig. 2).I S Coil current M B Braking torque n Speed t 1Brake response time 1)Switch-on procedure for operation with a rectifier without switching electron-ics 2)Switch-on procedure for operation with SEW rectifier with switching electronics, e.g. BGE (standard from size 112 upwards)t 1t 1t t t t t t I S I S M B M B n n 1)2)